Toilet bowl cleaners which are inserted in toilet tanks or toilet bowls have become commonplace. Typically, these bowl cleaners are in block or cake form and contain a surfactant and a water soluble dye in a carrier. The surfactant serves as the cleaning agent in the sense that it serves to prevent foreign matter from accumulating on the vitreous surfaces of the toilet bowl. From a psychological point of view, the dye is perhaps the most important component of toilet bowl cleaners since it imparts color to bowl water which serves as an indicator that the cleaner is functioning. The carrier serves its named function and also aids in controlling the rate and uniformity of solution of the surfactant and dye in tank or bowl waters.
There are two basic types of solid bowl cleaners sold commercially today. One consists of a mixture of surfactant and sodium sulphate with dye and other minor components. A second consists of a mixture of surfactant, urea, water soluble dye and other minor components. A third type of solid bowl cleaner could consist of surfactant and dye, however, such a composition would be excessively expensive in view of the relatively high cost of surfactant. Typical solid toilet bowl cleaner formulations of the foregoing types are exemplified by the copies of product data sheets from GAF Corporation, Union Carbide Corporation and Thompson-Hayward Chemical Company which are submitted with this application. Other solid toilet bowl cleaner compositions are described in U.S. Pat. Nos. 3,545,014; 3,760,429; 3,766,576 and 3,943,244, copies of which are submitted with this application.